In the field of cortical control signal acquisition, the recording system is a critical bottleneck for the passage of internal signals to external applications. It is agreed in this field that there are cortical control signals that can be used to control prosthetic devices and restore movement to paralyzed limbs, but these signals must be recorded and transmitted rapidly and intact. It is our goal to complete the development of a wireless, scalable 128-channel recording system, suitable for long-term human use. Applications range from communication for locked-in patients, to environmental control for the disabled, to motion restoration for the spinal cord injury population. Using two recently completed Phase I grants, Neural Signals has the necessary experience to meet this goal. The first Phase I effort (1 R43 NS-42478-01) designed and built an 8-channel, flexible, surface mount assembly, including a wireless inductive power supply, internal calibration, eight recording amplifiers, and eight FMtransmitters. The hybrid circuit developed during this grant resulted in a four-fold reduction in the recording system'svolume, compared to our previous implantable recording system. The second Phase I grant (1 R43 NS048706-01) has just been completed. During this grant, a 16-channel integrated circuit(1C) was fabricated to amplify signals from cortical electrodes and multiplex the signals using an analog scanner. Specific aims in Phase II are: A: Continue development of the integrated circuit device, (1) by incorporating voltage regulation and bias circuitry into the integrated circuit to minimize external semiconductor components; (2) by improving the floating gate recording amplifier and scanner based on knowledge gained during the Phase I development; (3) by continuing to develop (a) the power induction systemand (b) a unique synchronous scanner transmission system that will replace the present FM system. B: Miniaturize the Neurotrophic Electrode connections for reliable connection with the 1C device. C: Choose and implement new coatings and perform soak testing and stress testing of the implantable recording device consisting of the recording amplifiers, power supply, wireless signal transmission and attached electrodes.